Multitexturing: brightness / modulation?

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2 comments, last by MGB 19 years, 2 months ago
Hi all, Wondering if I'm doing something wrong here... I have a colour texture and a (greyscale) detail texture that I'm applying to an object using multitexturing. Thing is, I have to make the detail texture very bright for it not to have a darkening effect on the object I'm drawing. I would have thought that keeping the greyscale/intensity values at about 50% (~128) in the detail texture would mean keeping the same average brightness when applied with multitexturing..? Instead I find I have to boost the detail texture brightness so values are around 80-90% before it looks equivalent to the singly (colour) textured object. I load the detail texture using GL_LUMINANCE, and texture env is GL_REPLACE.
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Actually, thinking more about this - is it like a (source * detail) operation here, in which case it can *only* have a same or darker output..?

Ed: Hmmm, just found some info on a certain GL_COMBINE_EXT...

[Edited by - Aph3x on February 11, 2005 9:57:12 AM]
yes modulate is only gonna make it darker
with combine u could try add_signed which is A+B-0.5 though it might look washed out
Yer I tried a few - the signed one looks quite realistic & 'gritty' but too washed out in areas, like you say... :-/

Totally not mentioned in the Red Book, it being an extension n all that ;)

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